langchain/tests/unit_tests/chains/test_react.py
2022-11-08 22:17:10 -08:00

118 lines
3.9 KiB
Python

"""Unit tests for ReAct."""
from typing import Any, List, Mapping, Optional, Union
import pytest
from langchain.chains.llm import LLMChain
from langchain.chains.react.base import ReActChain, predict_until_observation
from langchain.docstore.base import Docstore
from langchain.docstore.document import Document
from langchain.llms.base import LLM
from langchain.prompts.prompt import Prompt
_PAGE_CONTENT = """This is a page about LangChain.
It is a really cool framework.
What isn't there to love about langchain?
Made in 2022."""
_FAKE_PROMPT = Prompt(input_variables=["input"], template="{input}")
class FakeListLLM(LLM):
"""Fake LLM for testing that outputs elements of a list."""
def __init__(self, responses: List[str]):
"""Initialize with list of responses."""
self.responses = responses
self.i = -1
def __call__(self, prompt: str, stop: Optional[List[str]] = None) -> str:
"""Increment counter, and then return response in that index."""
self.i += 1
return self.responses[self.i]
@property
def _identifying_params(self) -> Mapping[str, Any]:
return {}
class FakeDocstore(Docstore):
"""Fake docstore for testing purposes."""
def search(self, search: str) -> Union[str, Document]:
"""Return the fake document."""
document = Document(page_content=_PAGE_CONTENT)
return document
def test_predict_until_observation_normal() -> None:
"""Test predict_until_observation when observation is made normally."""
outputs = ["foo\nAction 1: search[foo]"]
fake_llm = FakeListLLM(outputs)
fake_llm_chain = LLMChain(llm=fake_llm, prompt=_FAKE_PROMPT)
ret_text, action, directive = predict_until_observation(fake_llm_chain, "", 1)
assert ret_text == outputs[0]
assert action == "search"
assert directive == "foo"
def test_predict_until_observation_repeat() -> None:
"""Test when no action is generated initially."""
outputs = ["foo", " search[foo]"]
fake_llm = FakeListLLM(outputs)
fake_llm_chain = LLMChain(llm=fake_llm, prompt=_FAKE_PROMPT)
ret_text, action, directive = predict_until_observation(fake_llm_chain, "", 1)
assert ret_text == "foo\nAction 1: search[foo]"
assert action == "search"
assert directive == "foo"
def test_predict_until_observation_error() -> None:
"""Test handling of generation of text that cannot be parsed."""
outputs = ["foo\nAction 1: foo"]
fake_llm = FakeListLLM(outputs)
fake_llm_chain = LLMChain(llm=fake_llm, prompt=_FAKE_PROMPT)
with pytest.raises(ValueError):
predict_until_observation(fake_llm_chain, "", 1)
def test_react_chain() -> None:
"""Test react chain."""
responses = [
"I should probably search\nAction 1: Search[langchain]",
"I should probably lookup\nAction 2: Lookup[made]",
"Ah okay now I know the answer\nAction 3: Finish[2022]",
]
fake_llm = FakeListLLM(responses)
react_chain = ReActChain(llm=fake_llm, docstore=FakeDocstore())
inputs = {"question": "when was langchain made"}
output = react_chain(inputs)
assert output["answer"] == "2022"
expected_full_output = (
"when was langchain made\n"
"Thought 1:I should probably search\n"
"Action 1: Search[langchain]\n"
"Observation 1: This is a page about LangChain.\n"
"Thought 2:I should probably lookup\n"
"Action 2: Lookup[made]\n"
"Observation 2: (Result 1/1) Made in 2022.\n"
"Thought 3:Ah okay now I know the answer\n"
"Action 3: Finish[2022]"
)
assert output["full_logic"] == expected_full_output
def test_react_chain_bad_action() -> None:
"""Test react chain when bad action given."""
responses = [
"I should probably search\nAction 1: BadAction[langchain]",
]
fake_llm = FakeListLLM(responses)
react_chain = ReActChain(llm=fake_llm, docstore=FakeDocstore())
with pytest.raises(ValueError):
react_chain.run("when was langchain made")